In the current debate on climate change, carbon dioxide (CO2) release and capture from fossil fuels is an important topic. Release and capture systems are often very large and expensive, and require a significant amount of energy. For example, before CO2 can be captured from fossil fuel plants, the flue gas from the plant must typically first be conditioned with a direct contact cooler (DCC).
In prior art applications such as that shown in FIG. 1 and the amine-based technology for large-scale, post-combustion CO2 capture (ECONAMINE FG PLUS™) plant that was built in Bellingham, Mass., which captured CO2 from combined cycle natural gas turbines, the gas enters a DCC then a CO2 absorber. For applications that contain species such as sulfur and chlorine compounds (e.g., coal, oil, coal derived fuels, bitumen, coke, sour gas, and other fossil fuels), the gas will typically first enter a flue gas desulfurization unit (FGD) before it enters the side of the DCC tower, turns 90 degrees, passes through irrigated packing, and exits through the top of the DCC tower, and finally enters a CO2 absorber. Thus, three separate vessels are used. Moreover, when a DCC is used downstream of another gas cleaning system such as the FGD system shown in FIG. 1, the ductwork arrangement is typically complicated because the gas exits the top of the FGD and is directed to the bottom of the adjacent DCC, where it flows to the top of the DCC and back down to ground level into a blower or booster fan.
Various other CO2 release and capture systems are also known including, for example, those having multi-stage FGDs (e.g., U.S. Pat. No. 7,514,053 to Johnson et al.), multistage DCCs (e.g., U.S. pat. appl. no. 2009/0148371 to Reddy et al.), and wet electrostatic precipitators (WESPs) coupled downstream of a FGD. In addition, U.S. Pat. No. 6,399,030 to Nolan discusses a combined removal system that separates CO2 and sulfur oxide gases from furnace flue gases in a single vessel with two chambers, and U.S. Pat. No. 7,867,322 to Gal discusses a gas cleaning system with a combined cooling/cleaning system downstream of a primary FGD, which functions to cool the gas and remove residual sulfur dioxide from the FGD product gas. However, none of the systems known to Applicant include a conditioning process with a primary absorber in a single tower, such that the gas can be conditioned prior to a CO2 absorption process.
These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Thus, there is still a need for systems and methods that include a primary absorber and gas conditioning system housed in a single vessel, such that a flue gas can be conditioned prior to a CO2 absorption process.